Commit b67c540b authored by Petr Machata's avatar Petr Machata Committed by David S. Miller
Browse files

net: dcb: Add priority-to-DSCP map getters 



On ingress, a network device such as a switch assigns to packets
priority based on various criteria. Common options include interpreting
PCP and DSCP fields according to user configuration. When a packet
egresses the switch, a reverse process may rewrite PCP and/or DSCP
values according to packet priority.

The following three functions support a) obtaining a DSCP-to-priority
map or vice versa, and b) finding default-priority entries in APP
database.

The DCB subsystem supports for APP entries a very generous M:N mapping
between priorities and protocol identifiers. Understandably,
several (say) DSCP values can map to the same priority. But this
asymmetry holds the other way around as well--one priority can map to
several DSCP values. For this reason, the following functions operate in
terms of bitmaps, with ones in positions that match some APP entry.

- dcb_ieee_getapp_dscp_prio_mask_map() to compute for a given netdevice
  a map of DSCP-to-priority-mask, which gives for each DSCP value a
  bitmap of priorities related to that DSCP value by APP, along the
  lines of dcb_ieee_getapp_mask().

- dcb_ieee_getapp_prio_dscp_mask_map() similarly to compute for a given
  netdevice a map from priorities to a bitmap of DSCPs.

- dcb_ieee_getapp_default_prio_mask() which finds all default-priority
  rules for a given port in APP database, and returns a mask of
  priorities allowed by these default-priority rules.

Signed-off-by: default avatarPetr Machata <petrm@mellanox.com>
Signed-off-by: default avatarIdo Schimmel <idosch@mellanox.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 08193d1a

include/net/dcbnl.h

+13 −0
Original line number Diff line number Diff line
@@ -34,6 +34,19 @@ int dcb_ieee_setapp(struct net_device *, struct dcb_app *); 
int dcb_ieee_delapp(struct net_device *, struct dcb_app *);

u8 dcb_ieee_getapp_mask(struct net_device *, struct dcb_app *);



struct dcb_ieee_app_prio_map {

	u64 map[IEEE_8021QAZ_MAX_TCS];

};

void dcb_ieee_getapp_prio_dscp_mask_map(const struct net_device *dev,

					struct dcb_ieee_app_prio_map *p_map);



struct dcb_ieee_app_dscp_map {

	u8 map[64];

};

void dcb_ieee_getapp_dscp_prio_mask_map(const struct net_device *dev,

					struct dcb_ieee_app_dscp_map *p_map);

u8 dcb_ieee_getapp_default_prio_mask(const struct net_device *dev);



int dcbnl_ieee_notify(struct net_device *dev, int event, int cmd,

		      u32 seq, u32 pid);

int dcbnl_cee_notify(struct net_device *dev, int event, int cmd,

net/dcb/dcbnl.c

+86 −0
Original line number Diff line number Diff line
@@ -1958,6 +1958,92 @@ int dcb_ieee_delapp(struct net_device *dev, struct dcb_app *del) 
}

EXPORT_SYMBOL(dcb_ieee_delapp);



/**

 * dcb_ieee_getapp_prio_dscp_mask_map - For a given device, find mapping from

 * priorities to the DSCP values assigned to that priority. Initialize p_map

 * such that each map element holds a bit mask of DSCP values configured for

 * that priority by APP entries.

 */

void dcb_ieee_getapp_prio_dscp_mask_map(const struct net_device *dev,

					struct dcb_ieee_app_prio_map *p_map)

{

	int ifindex = dev->ifindex;

	struct dcb_app_type *itr;

	u8 prio;



	memset(p_map->map, 0, sizeof(p_map->map));



	spin_lock_bh(&dcb_lock);

	list_for_each_entry(itr, &dcb_app_list, list) {

		if (itr->ifindex == ifindex &&

		    itr->app.selector == IEEE_8021QAZ_APP_SEL_DSCP &&

		    itr->app.protocol < 64 &&

		    itr->app.priority < IEEE_8021QAZ_MAX_TCS) {

			prio = itr->app.priority;

			p_map->map[prio] |= 1ULL << itr->app.protocol;

		}

	}

	spin_unlock_bh(&dcb_lock);

}

EXPORT_SYMBOL(dcb_ieee_getapp_prio_dscp_mask_map);



/**

 * dcb_ieee_getapp_dscp_prio_mask_map - For a given device, find mapping from

 * DSCP values to the priorities assigned to that DSCP value. Initialize p_map

 * such that each map element holds a bit mask of priorities configured for a

 * given DSCP value by APP entries.

 */

void

dcb_ieee_getapp_dscp_prio_mask_map(const struct net_device *dev,

				   struct dcb_ieee_app_dscp_map *p_map)

{

	int ifindex = dev->ifindex;

	struct dcb_app_type *itr;



	memset(p_map->map, 0, sizeof(p_map->map));



	spin_lock_bh(&dcb_lock);

	list_for_each_entry(itr, &dcb_app_list, list) {

		if (itr->ifindex == ifindex &&

		    itr->app.selector == IEEE_8021QAZ_APP_SEL_DSCP &&

		    itr->app.protocol < 64 &&

		    itr->app.priority < IEEE_8021QAZ_MAX_TCS)

			p_map->map[itr->app.protocol] |= 1 << itr->app.priority;

	}

	spin_unlock_bh(&dcb_lock);

}

EXPORT_SYMBOL(dcb_ieee_getapp_dscp_prio_mask_map);



/**

 * Per 802.1Q-2014, the selector value of 1 is used for matching on Ethernet

 * type, with valid PID values >= 1536. A special meaning is then assigned to

 * protocol value of 0: "default priority. For use when priority is not

 * otherwise specified".

 *

 * dcb_ieee_getapp_default_prio_mask - For a given device, find all APP entries

 * of the form {$PRIO, ETHERTYPE, 0} and construct a bit mask of all default

 * priorities set by these entries.

 */

u8 dcb_ieee_getapp_default_prio_mask(const struct net_device *dev)

{

	int ifindex = dev->ifindex;

	struct dcb_app_type *itr;

	u8 mask = 0;



	spin_lock_bh(&dcb_lock);

	list_for_each_entry(itr, &dcb_app_list, list) {

		if (itr->ifindex == ifindex &&

		    itr->app.selector == IEEE_8021QAZ_APP_SEL_ETHERTYPE &&

		    itr->app.protocol == 0 &&

		    itr->app.priority < IEEE_8021QAZ_MAX_TCS)

			mask |= 1 << itr->app.priority;

	}

	spin_unlock_bh(&dcb_lock);



	return mask;

}

EXPORT_SYMBOL(dcb_ieee_getapp_default_prio_mask);



static int __init dcbnl_init(void)

{

	INIT_LIST_HEAD(&dcb_app_list);

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